The unidentified passengers have already “paid a significant deposit” for the approximately one-week trip, according to Musk's announcement, and they will begin training later this year. Their private mission will be launched on the Crew Dragon spacecraft using the Falcon Heavy rocket, which is set to take off for its first test run this summer, and will circle the moon before returning to Earth.

Lift-off will take place at Kennedy Space Center's Pad 39A, the same launch pad used by the Apollo program, Musk notes.

“Like the Apollo astronauts before them, these individuals will travel into space carrying the hopes and dreams of all humankind, driven by the universal human spirit of exploration,” the announcement reads.

Musk says SpaceX plans to do one or two of these trips a year in hopes of driving “significant” revenue, and adds that privately crewed missions have been "encouraged" by NASA.

To prepare, a Crew Dragon will fly in automatic mode (without humans) to the International Space Station later this year, according to Musk. Then, it will complete the trip again with crew in the second quarter of next year, before the amateur space travelers take flight.